Calcium Chelate Was Prepared By Enzymatic Hydrolysis And Fermentation

Donkey bone is a by-product of donkey meat processing.It is rich in protein and calcium.H ow to make full use of this precious resource and increase its added value is of great significance to actual production.In this experiment,enzymatic hydrolysis-fermentation technology was used to prepare amino acid chelated calcium.The experiment firstly graded and ground donkey bone to o btain ultrafine bone mud,then enzymatically digested the bone mud,and fermented the enzymatica lly precipitated,The amino acid source and calcium source obtained after enzymatic hydrolysis and fermentation are reacted to obtain amino acid chelated calcium.Ultraviolet spectroscopy,infrared spectroscopy and scanning electron microscopy were used to analyze the structural characterization of amino acid chelated calcium,and to determine its antioxidant,bacteriostatic and digestive proper ties.The main research contents and results are as follows:1.Study the best enzymolysis process of donkey bone mud.Five kinds of proteases(trypsin,complex protease,pepsin,flavor protease and papain)were selected for enzymatic hydrolysis of bo ne mud under their respective optimal enzymolysis conditions,and the types of enzymes and doubl e Enzyme combination method,and the free amino acid composition and antioxidant activity of th e enzymolysis solution were measured.The results show that the partial hydrolysis of flavor protea se and compound protease is the best hydrolysis process,and the optimal enzymolysis conditions a re: first add flavor protease,at 50?,pH 7.0,add enzyme amount 1.5%,solid-liquid ratio 1: 2 A fter 3 hours of enzymatic hydrolysis under conditions,compound protease was added,the solid-liq uid ratio was 1: 2,the amount of enzyme added was 2.5%,and the enzymolysis time was 4 hour s.Under this condition,the degree of hydrolysis and the yield of soluble polypeptide reached 15.74% and 24.12%;the enzymolysis solution contained 17 amino acids,including alanine,phenylalani ne,valine,leucine,tyrosine,The content of lysine,arginine,proline and glycine is higher than 30mg/100mL.Essential amino acids account for 47.41% of the total amino acids;the resulting en zymolysis solution has a good reduction effect.When the concentration is 10mg/mL,the cleara nce rate of the enzymolysis product to superoxide anion free radicals,hydroxyl free radicals and DPPH free radicals respectively reaches 31.65%,44.40% and 71.43%.2.Collect the precipitate after enzymatic hydrolysis,and select eight kinds of fermentation age nts to ferment the enzymatic hydrolysate to obtain more soluble calcium ions,amino acids and pe ptides.The optimal fermentation agent was screened based on soluble calcium content and soluble peptide yield,and the optimal fermentation process was optimized through a single factor test and Box-Behnken center combination design.The experiment determined that the best starter was Lyoc arni SBM-52,and the optimal process parameters were: inoculation volume 0.33%,substrate conce ntration 23.60%,fermentation time 29.40 h,fermentation under this condition,soluble calcium cont ent was 268.37mg/100 mL.3.Chelate the amino acid source and calcium source obtained after enzymolysis and fermentat ion to make amino acid chelated calcium.Using the chelation rate as an indicator,determine the best chelation process through single factor test and orthogonal test: volume ratio of enzymolysis li quid to fermentation liquid: 2: 3,pH 6,reaction temperature 50 ?,reaction time 60 min,this Th e chelation rate under the conditions is 59.04%.4.Infrared spectroscopy,ultraviolet spectroscopy and scanning electron microscopy were used to identify the structure of the amino acid chelated calcium prepared in the earlier stage,and to a nalyze its antioxidant,bacteriostatic and digestive properties.The results show that: using ultraviole t and infrared spectroscopy analysis,it is found that the chelated products have significantly chang ed infrared and ultraviolet spectra compared with unchelated compounds;by scanning electron micr oscopy,it can be clearly seen that more "white crystals" are chelating On the surface of the prod uct.The above results confirm the formation of amino acid chelated calcium;compared with unch elated compounds,the ability of amino acid chelated calcium to scavenge DPPH free radicals,sup eroxide anion free radicals and hydroxyl free radicals is enhanced.The chelate has antibacterial eff ect on Staphylococcus aureus,Escherichia coli and Salmonella,among which the antibacterial effec t on Staphylococcus aureus is the most significant;After 2 hours of digestion in the environment,the calcium release performance reached 90.38%,and the calcium dissolution rate after simulated ntestinal digestion remained at 42.50%,indicating that the chelate has good digestive properties.